Lemma 2.2 [1]} 
Let \(f(z)\)  be a meromorphic function of finite order and \(c \in \mathbb {C}\setminus \lbrace 0\rbrace \) . Then
\(m\left(r,\frac{f(z+c)}{f(z)}\right)+m\left(r,\frac{f(z)}{f(z+c)}\right)= S(r,f).\) 

